X301 Power Savings

x301 Power Savings

The standard Fedora configuration provides for a lot of leeway in power savings. Here are the items I have modified that got me from around 11W to around 7W. powertop is an invaluable tool in figuring out how much power is being drawn by each component, not to mention seeing your progress. A lot of this information is covered in other pages, but this is specific to the x301. Note that these settings were tested on an x301 running a fresh Fedora 11 Beta install.

I don't use bluetooth on a regular day...

echo disabled > /proc/acpi/ibm/bluetooth

The video system keeps one or more of the external connectors powered up at all times.

By default, the wifi driver keeps the card at the maximum power setting for better performance. If you are just browsing the web or not using a lot of bandwidth significant savings can be had by reducing this setting.1

echo 5 > /sys/class/net/wlan0/device/power_level

Newer kernels are much smarter about how they load the cores on a CPU, this setting tells it to be more power efficient rather than performance oriented.2

echo 1 > /sys/devices/system/cpu/sched_mc_power_savings

Hal will constantly poll the cdrom to see if a disk has been inserted and if it should mount and open it for you in X. Disabling this allows the cpu to sleep longer.

hal-disable-polling --device /dev/cdrom

New features in the SATA driver allows it to power down the link when not utilized, make sure to enable on all paths with3

for foo in /sys/class/scsi_host/host*/link_power_management_policy;
do echo min_power > $foo;
done

Similar savings can be had by setting the pcie bus to a more power-friendly mode